This invention relates to multipacks, that is to say, packages in which a plurality of articles are secured together for retailing as a single item. The invention has particular application to multipacks in which a plurality of cans, especially cans for carbonated beverages and having easy opening end closures at one end, are releasably secured together in an array by a sheet plastics coupler such as is marketed in UK under the trade name Hi-Cone (Registered Trade Mark); the coupler has apertures through which end closures of the cans are made to project, the size of the apertures being such that the cans are then tightly held in position by tension in the coupler material.
Although they are cheap to manufacture and apply, sheet plastics couplers for can multipacks suffer from the disadvantage that they are difficult to print, and moreover do not provide any substantial area on which promotional matter or technical information (e.g. a bar coding) could be printed. Furthermore, the can end closures under which the coupler is located are unprotected from dust and other contamination, therefore, particularly if they are of the easy-opening kind, these closures will often require to be cleaned if the product in the cans is to be dispensed hygenically.
It has already been proposed to provide a cover and display attachment for a container multipack having a sheet plastics coupler. The attachment is made of paperboard or like material and is in the form of a blank which is disposed to overlie the can end closures but separated from the double seams of the closures by edge portions of the coupler material formed around the container-receiving apertures in the coupler. The blank is wholly planar, being devoid of any folding or other deformation. It is attached to the coupler by heat sealing to the upper faces presented above the double seams by the above-mentioned edge portions of the coupler.
This arrangement, however, suffers from various shortcomings, both in the sealing of the attachment to the multipack and in the efficacy of the attachment in use. Among these shortcomings are the following:
(a) The formation of the edge portions of the coupler may require the coupler to be thermoformed rather than stamped. This will tend to increase manufacturing costs and reduce production rates.
(b) Because of the existence of the edge portions, the coupler no longer possesses continuous free edges which can securely lodge beneath the double seams of the containers to hold the coupler firmly in position.
(c) Engagement of the coupler beneath the container double seams takes place essentially along fold lines by which the edge portions are carried from the remainder of the coupler; any attempt to use the cover and display attachment to carry the multipack will tend to unfold these fold lines and so release the containers prematurely.
(d) It is difficult to provide the cover and display attachment with a satisfactory easy-open facility, for example tear lines in the board material, without introducing a tendancy for the attachment to tear or otherwise become damaged during normal handling, transit etc. of the multipack.
(e) The cover and display attachment is closely coupled to the underlying containers via the coupler and is therefore unable to accommodate itself to any great extent to relative movement of the containers, for example when one container is tilted or lifted in relation to the others; because of this lack of flexibility, the attachment can, in some circumstances, be inadvertently torn or detached from the coupler.
(f) Because the attachment is not folded or otherwise deformed, heat sealing is only practicable by heat conduction through the attachment material; this is inherently slow, and liable to impose a substantial limitation on the throughput of an automatic machine for assembling the attachments on a succession of the multipacks passing along a conveyor.